This advisory also applies to the corresponding versions ofKubuntu, Edubuntu, and Xubuntu.

The problem can be corrected by upgrading your system to thefollowing package versions:

Ubuntu 6.06 LTS: libkrb53 1.4.3-5ubuntu0.10

Ubuntu 8.04 LTS: libkrb53 1.6.dfsg.3~beta1-2ubuntu1.3

Ubuntu 8.10: libkrb53 1.6.dfsg.4~beta1-3ubuntu0.3

Ubuntu 9.04: libkrb53 1.6.dfsg.4~beta1-5ubuntu2.2

Ubuntu 9.10: libk5crypto3 1.7dfsg~beta3-1ubuntu0.3

In general, a standard system upgrade is sufficient to effect thenecessary changes.

Details follow:

It was discovered that Kerberos did not correctly handle invalid AESblocks. An unauthenticated remote attacker could send specially craftedtraffic that would crash the KDC service, leading to a denial of service,or possibly execute arbitrary code with root privileges.